It is well known that in a conventional lateral power device, the reverse voltage is sustained by a lightly doped semiconductor drift region, such as the Lateral Double Diffused Metal Oxide Semiconductor (LDMOS). If junction depth and doping concentration of drift region meet the RESURF (reduce the device surface field by reinforcing the body field) condition, the drift region will be fully depleted and space charges are introduced. Therefore, the LDMOS is capable of withstanding high voltage at the off-state. The RESURE condition reported by literature [J. A. Appels, M. G. Collet. P. Hart, H. Vaes, J. Verhoeven. Thin-layer HV-devices [J]. Philips Journal of Research, 1980, 35(1):1˜13] is as below:
            N      epi        ⁢          t      epi        ≤      2    ×          10      12        ⁢                            N          epi                                      P            sub                    +                      N            epi                                ≤      1.4    ×          10      12        ⁢          cm              -        2            
The Psub, Nepi, tepi are the doping concentration of P type substrate, doping concentration and junction depth of the drift region, respectively. Apparently, higher doping concentration or larger junction depth for drift region always provides lower specific on-resistance. However, observing from the above equation, the RESURF condition determines the upper limit for the product of the drift region doping concentration and junction depth. Consequently, the device specific on-resistance is confined to meet the RESURF condition for high breakdown voltage. In different from conventional LDMOS which only used N− doping in drift region, lateral Super Junction device used the drift region with alternating P− and N− doping. Because the mutual diffusing effect happens between N− and P− drift region, higher drift region doping concentration is allowed in the Super Junction so that the specific on-resistance is reduced. Although its performance is better than that of the RESURF LDMOS, the conduction of Super Junction still relies on drift region doping; its specific on-resistance is a limited under given breakdown voltage condition.
Under the same specific on-resistance, the breakdown voltage improvement is realized by the optimization of electric field distribution at the power device blocking state, and no additional methods are used to reduce the device specific on-resistance for above conventional techniques. Consequently, the specific on-resistance of the power device are still determined by drift region doping concentration and junction depth, the trade-off between high breakdown voltage and low specific on-resistance still exists. As revealed in literature [S. E. D. Habib, The ALDMOST: A New Power MOS Transistor. IEEE Electr. Dev. Lett. 8, 257-259 (1987)] and [B. J. Baliga, T. Syau, and P. Venkatraman: The accumulation-mode field effect transistor: A new ultralow on-resistance MOSFET. IEEE Electr Dev. Lett. 13, 427-429 (1992)], the accumulation effects can be introduced to the drift region by using thin SiO2 dielectric, so that the electron carrier density is boosted with no additional doping, therefore, the specific on-resistance is reduced with the effect of accumulation effect under fixed drift region doping concentration and junction depth condition. However, because the permittivity of the SiO2 is very low, the accumulation effect is limited; and the thin SiO2 is also fragile for high voltage. Furthermore, the low permittivity of the SiO2 may cause the potential gathering, which is negative for high breakdown voltage. In US patent, [X. Chen, Super-junction voltage sustaining layers with alternating semiconductor and high-K dielectric regions. U.S. Pat. No. 7,230,310, Jun. 12, (2007)], the high permittivity pillars are inserted into the drift region to modulate the potential distribution and improve the breakdown voltage, however, the high permittivity pillars has completely no contact with the gate, the carrier accumulation effect therefore will not happen at the device on state. As a result, the device specific on-resistance indicates no significant decrease than that of the Super junction.